var a = parseInt(prompt("请输入第一个数",""));
var b = parseInt(prompt("请输入第二个数",""));
var c = a+b;
var d = a-b;
var f = a*b;
var g = a/b;
alert(a+"+"+b+"="+c+"\n"+a+"-"+b+"="+d+"\n"+a+"*"+b+"="+f+"\n"+a+"/"+b+"="+g);